Merge pull request #3224 from cfromknecht/wtserver-key-family

watchtower: use separate key family for wtserver public key, add watchtower subserver

lnrpc/watchtowerrpc/config_active.go

@@ -0,0 +1,13 @@
+// +build watchtowerrpc
+
+package watchtowerrpc
+
+// Config is the primary configuration struct for the watchtower RPC server. It
+// contains all items required for the RPC server to carry out its duties. The
+// fields with struct tags are meant to parsed as normal configuration options,
+// while if able to be populated, the latter fields MUST also be specified.
+type Config struct {
+	// Tower is the active watchtower which serves as the primary source for
+	// information presented via RPC.
+	Tower WatchtowerBackend
+}

lnrpc/watchtowerrpc/config_default.go

@@ -0,0 +1,6 @@
+// +build !watchtowerrpc
+
+package watchtowerrpc
+
+// Config is empty for non-watchtowerrpc builds.
+type Config struct{}

lnrpc/watchtowerrpc/driver.go

@@ -0,0 +1,55 @@
+// +build watchtowerrpc
+
+package watchtowerrpc
+
+import (
+	"fmt"
+
+	"github.com/lightningnetwork/lnd/lnrpc"
+)
+
+// createNewSubServer is a helper method that will create the new sub server
+// given the main config dispatcher method. If we're unable to find the config
+// that is meant for us in the config dispatcher, then we'll exit with an
+// error.
+func createNewSubServer(configRegistry lnrpc.SubServerConfigDispatcher) (
+	lnrpc.SubServer, lnrpc.MacaroonPerms, error) {
+
+	// We'll attempt to look up the config that we expect, according to our
+	// subServerName name. If we can't find this, then we'll exit with an
+	// error, as we're unable to properly initialize ourselves without this
+	// config.
+	subServerConf, ok := configRegistry.FetchConfig(subServerName)
+	if !ok {
+		return nil, nil, fmt.Errorf("unable to find config for "+
+			"subserver type %s", subServerName)
+	}
+
+	// Now that we've found an object mapping to our service name, we'll
+	// ensure that it's the type we need.
+	config, ok := subServerConf.(*Config)
+	if !ok {
+		return nil, nil, fmt.Errorf("wrong type of config for "+
+			"subserver %s, expected %T got %T", subServerName,
+			&Config{}, subServerConf)
+	}
+
+	return New(config)
+}
+
+func init() {
+	subServer := &lnrpc.SubServerDriver{
+		SubServerName: subServerName,
+		New: func(c lnrpc.SubServerConfigDispatcher) (lnrpc.SubServer,
+			lnrpc.MacaroonPerms, error) {
+			return createNewSubServer(c)
+		},
+	}
+
+	// If the build tag is active, then we'll register ourselves as a
+	// sub-RPC server within the global lnrpc package namespace.
+	if err := lnrpc.RegisterSubServer(subServer); err != nil {
+		panic(fmt.Sprintf("failed to register sub server driver "+
+			"'%s': %v", subServerName, err))
+	}
+}

lnrpc/watchtowerrpc/handler.go

@@ -0,0 +1,131 @@
+// +build watchtowerrpc
+
+package watchtowerrpc
+
+import (
+	"context"
+	"errors"
+	fmt "fmt"
+
+	"github.com/lightningnetwork/lnd/lnrpc"
+	"google.golang.org/grpc"
+	"gopkg.in/macaroon-bakery.v2/bakery"
+)
+
+const (
+	// subServerName is the name of the sub rpc server. We'll use this name
+	// to register ourselves, and we also require that the main
+	// SubServerConfigDispatcher instance recognizes it as the name of our
+	// RPC service.
+	subServerName = "WatchtowerRPC"
+)
+
+var (
+	// macPermissions maps RPC calls to the permissions they require.
+	macPermissions = map[string][]bakery.Op{
+		"/watchtowerrpc.Watchtower/GetInfo": {{
+			Entity: "info",
+			Action: "read",
+		}},
+	}
+
+	// ErrTowerNotActive signals that RPC calls cannot be processed because
+	// the watchtower is not active.
+	ErrTowerNotActive = errors.New("watchtower not active")
+)
+
+// Handler is the RPC server we'll use to interact with the backing active
+// watchtower.
+type Handler struct {
+	cfg Config
+}
+
+// A compile time check to ensure that Handler fully implements the Handler gRPC
+// service.
+var _ WatchtowerServer = (*Handler)(nil)
+
+// New returns a new instance of the Watchtower sub-server. We also return the
+// set of permissions for the macaroons that we may create within this method.
+// If the macaroons we need aren't found in the filepath, then we'll create them
+// on start up. If we're unable to locate, or create the macaroons we need, then
+// we'll return with an error.
+func New(cfg *Config) (*Handler, lnrpc.MacaroonPerms, error) {
+	return &Handler{*cfg}, macPermissions, nil
+}
+
+// Start launches any helper goroutines required for the Handler to function.
+//
+// NOTE: This is part of the lnrpc.SubServer interface.
+func (c *Handler) Start() error {
+	return nil
+}
+
+// Stop signals any active goroutines for a graceful closure.
+//
+// NOTE: This is part of the lnrpc.SubServer interface.
+func (c *Handler) Stop() error {
+	return nil
+}
+
+// Name returns a unique string representation of the sub-server. This can be
+// used to identify the sub-server and also de-duplicate them.
+//
+// NOTE: This is part of the lnrpc.SubServer interface.
+func (c *Handler) Name() string {
+	return subServerName
+}
+
+// RegisterWithRootServer will be called by the root gRPC server to direct a sub
+// RPC server to register itself with the main gRPC root server. Until this is
+// called, each sub-server won't be able to have requests routed towards it.
+//
+// NOTE: This is part of the lnrpc.SubServer interface.
+func (c *Handler) RegisterWithRootServer(grpcServer *grpc.Server) error {
+	// We make sure that we register it with the main gRPC server to ensure
+	// all our methods are routed properly.
+	RegisterWatchtowerServer(grpcServer, c)
+
+	log.Debugf("Watchtower RPC server successfully register with root " +
+		"gRPC server")
+
+	return nil
+}
+
+// AddTower adds a new watchtower reachable at the given address and considers
+// it for new sessions. If the watchtower already exists, then any new addresses
+// included will be considered when dialing it for session negotiations and
+// backups.
+func (c *Handler) GetInfo(ctx context.Context,
+	req *GetInfoRequest) (*GetInfoResponse, error) {
+
+	if err := c.isActive(); err != nil {
+		return nil, err
+	}
+
+	pubkey := c.cfg.Tower.PubKey().SerializeCompressed()
+
+	var listeners []string
+	for _, addr := range c.cfg.Tower.ListeningAddrs() {
+		listeners = append(listeners, addr.String())
+	}
+
+	var uris []string
+	for _, addr := range c.cfg.Tower.ExternalIPs() {
+		uris = append(uris, fmt.Sprintf("%x@%v", pubkey, addr))
+	}
+
+	return &GetInfoResponse{
+		Pubkey:    pubkey,
+		Listeners: listeners,
+		Uris:      uris,
+	}, nil
+}
+
+// isActive returns nil if the tower backend is initialized, and the Handler can
+// proccess RPC requests.
+func (c *Handler) isActive() error {
+	if c.cfg.Tower != nil {
+		return nil
+	}
+	return ErrTowerNotActive
+}

lnrpc/watchtowerrpc/interface.go

@@ -0,0 +1,23 @@
+package watchtowerrpc
+
+import (
+	"net"
+
+	"github.com/btcsuite/btcd/btcec"
+)
+
+// WatchtowerBackend abstracts access to the watchtower information that is
+// served via RPC connections.
+type WatchtowerBackend interface {
+	// PubKey returns the public key for the watchtower used to
+	// authentication and encrypt traffic with clients.
+	PubKey() *btcec.PublicKey
+
+	// ListeningAddrs returns the listening addresses where the watchtower
+	// server can accept client connections.
+	ListeningAddrs() []net.Addr
+
+	// ExternalIPs returns the addresses where the watchtower can be reached
+	// by clients externally.
+	ExternalIPs() []net.Addr
+}

lnrpc/watchtowerrpc/log.go

@@ -0,0 +1,47 @@
+package watchtowerrpc
+
+import (
+	"github.com/btcsuite/btclog"
+	"github.com/lightningnetwork/lnd/build"
+)
+
+// Subsystem defines the logging code for this subsystem.
+const Subsystem = "WRPC"
+
+// log is a logger that is initialized with no output filters. This means the
+// package will not perform any logging by default until the caller requests it.
+var log btclog.Logger
+
+// The default amount of logging is none.
+func init() {
+	UseLogger(build.NewSubLogger(Subsystem, nil))
+}
+
+// DisableLog disables all library log output. Logging output is disabled by by
+// default until UseLogger is called.
+func DisableLog() {
+	UseLogger(btclog.Disabled)
+}
+
+// UseLogger uses a specified Logger to output package logging info. This
+// should be used in preference to SetLogWriter if the caller is also using
+// btclog.
+func UseLogger(logger btclog.Logger) {
+	log = logger
+}
+
+// logClosure is used to provide a closure over expensive logging operations so
+// don't have to be performed when the logging level doesn't warrant it.
+type logClosure func() string
+
+// String invokes the underlying function and returns the result.
+func (c logClosure) String() string {
+	return c()
+}
+
+// newLogClosure returns a new closure over a function that returns a string
+// which itself provides a Stringer interface so that it can be used with the
+// logging system.
+func newLogClosure(c func() string) logClosure {
+	return logClosure(c)
+}

lnrpc/watchtowerrpc/watchtower.pb.go

@@ -0,0 +1,217 @@
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// source: watchtowerrpc/watchtower.proto
+
+package watchtowerrpc
+
+import (
+	context "context"
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	grpc "google.golang.org/grpc"
+	math "math"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
+type GetInfoRequest struct {
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *GetInfoRequest) Reset()         { *m = GetInfoRequest{} }
+func (m *GetInfoRequest) String() string { return proto.CompactTextString(m) }
+func (*GetInfoRequest) ProtoMessage()    {}
+func (*GetInfoRequest) Descriptor() ([]byte, []int) {
+	return fileDescriptor_9f019c0e859ad3d6, []int{0}
+}
+
+func (m *GetInfoRequest) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_GetInfoRequest.Unmarshal(m, b)
+}
+func (m *GetInfoRequest) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_GetInfoRequest.Marshal(b, m, deterministic)
+}
+func (m *GetInfoRequest) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_GetInfoRequest.Merge(m, src)
+}
+func (m *GetInfoRequest) XXX_Size() int {
+	return xxx_messageInfo_GetInfoRequest.Size(m)
+}
+func (m *GetInfoRequest) XXX_DiscardUnknown() {
+	xxx_messageInfo_GetInfoRequest.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_GetInfoRequest proto.InternalMessageInfo
+
+type GetInfoResponse struct {
+	/// The public key of the watchtower.
+	Pubkey []byte `protobuf:"bytes,1,opt,name=pubkey,proto3" json:"pubkey,omitempty"`
+	/// The listening addresses of the watchtower.
+	Listeners []string `protobuf:"bytes,2,rep,name=listeners,proto3" json:"listeners,omitempty"`
+	/// The URIs of the watchtower.
+	Uris                 []string `protobuf:"bytes,3,rep,name=uris,proto3" json:"uris,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *GetInfoResponse) Reset()         { *m = GetInfoResponse{} }
+func (m *GetInfoResponse) String() string { return proto.CompactTextString(m) }
+func (*GetInfoResponse) ProtoMessage()    {}
+func (*GetInfoResponse) Descriptor() ([]byte, []int) {
+	return fileDescriptor_9f019c0e859ad3d6, []int{1}
+}
+
+func (m *GetInfoResponse) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_GetInfoResponse.Unmarshal(m, b)
+}
+func (m *GetInfoResponse) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_GetInfoResponse.Marshal(b, m, deterministic)
+}
+func (m *GetInfoResponse) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_GetInfoResponse.Merge(m, src)
+}
+func (m *GetInfoResponse) XXX_Size() int {
+	return xxx_messageInfo_GetInfoResponse.Size(m)
+}
+func (m *GetInfoResponse) XXX_DiscardUnknown() {
+	xxx_messageInfo_GetInfoResponse.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_GetInfoResponse proto.InternalMessageInfo
+
+func (m *GetInfoResponse) GetPubkey() []byte {
+	if m != nil {
+		return m.Pubkey
+	}
+	return nil
+}
+
+func (m *GetInfoResponse) GetListeners() []string {
+	if m != nil {
+		return m.Listeners
+	}
+	return nil
+}
+
+func (m *GetInfoResponse) GetUris() []string {
+	if m != nil {
+		return m.Uris
+	}
+	return nil
+}
+
+func init() {
+	proto.RegisterType((*GetInfoRequest)(nil), "watchtowerrpc.GetInfoRequest")
+	proto.RegisterType((*GetInfoResponse)(nil), "watchtowerrpc.GetInfoResponse")
+}
+
+func init() { proto.RegisterFile("watchtowerrpc/watchtower.proto", fileDescriptor_9f019c0e859ad3d6) }
+
+var fileDescriptor_9f019c0e859ad3d6 = []byte{
+	// 213 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0x92, 0x2b, 0x4f, 0x2c, 0x49,
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+	0x0a, 0x8c, 0x1a, 0x3c, 0x41, 0x50, 0x9e, 0x90, 0x0c, 0x17, 0x67, 0x4e, 0x66, 0x71, 0x49, 0x6a,
+	0x5e, 0x6a, 0x51, 0xb1, 0x04, 0x93, 0x02, 0xb3, 0x06, 0x67, 0x10, 0x42, 0x40, 0x48, 0x88, 0x8b,
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+	0x49, 0xc9, 0xe1, 0x92, 0x86, 0xb8, 0xd0, 0xc9, 0x34, 0xca, 0x38, 0x3d, 0xb3, 0x24, 0xa3, 0x34,
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+	0xb5, 0xa4, 0x3c, 0xbf, 0x28, 0x5b, 0x3f, 0x27, 0x2f, 0x45, 0x3f, 0x27, 0x0f, 0x35, 0x3c, 0x8a,
+	0x0a, 0x92, 0x93, 0xd8, 0xc0, 0x61, 0x62, 0x0c, 0x08, 0x00, 0x00, 0xff, 0xff, 0xa1, 0x23, 0x0b,
+	0x68, 0x35, 0x01, 0x00, 0x00,
+}
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ context.Context
+var _ grpc.ClientConn
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the grpc package it is being compiled against.
+const _ = grpc.SupportPackageIsVersion4
+
+// WatchtowerClient is the client API for Watchtower service.
+//
+// For semantics around ctx use and closing/ending streaming RPCs, please refer to https://godoc.org/google.golang.org/grpc#ClientConn.NewStream.
+type WatchtowerClient interface {
+	//* lncli: tower info
+	//GetInfo returns general information concerning the companion watchtower
+	//including it's public key and URIs where the server is currently
+	//listening for clients.
+	GetInfo(ctx context.Context, in *GetInfoRequest, opts ...grpc.CallOption) (*GetInfoResponse, error)
+}
+
+type watchtowerClient struct {
+	cc *grpc.ClientConn
+}
+
+func NewWatchtowerClient(cc *grpc.ClientConn) WatchtowerClient {
+	return &watchtowerClient{cc}
+}
+
+func (c *watchtowerClient) GetInfo(ctx context.Context, in *GetInfoRequest, opts ...grpc.CallOption) (*GetInfoResponse, error) {
+	out := new(GetInfoResponse)
+	err := c.cc.Invoke(ctx, "/watchtowerrpc.Watchtower/GetInfo", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// WatchtowerServer is the server API for Watchtower service.
+type WatchtowerServer interface {
+	//* lncli: tower info
+	//GetInfo returns general information concerning the companion watchtower
+	//including it's public key and URIs where the server is currently
+	//listening for clients.
+	GetInfo(context.Context, *GetInfoRequest) (*GetInfoResponse, error)
+}
+
+func RegisterWatchtowerServer(s *grpc.Server, srv WatchtowerServer) {
+	s.RegisterService(&_Watchtower_serviceDesc, srv)
+}
+
+func _Watchtower_GetInfo_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(GetInfoRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(WatchtowerServer).GetInfo(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/watchtowerrpc.Watchtower/GetInfo",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(WatchtowerServer).GetInfo(ctx, req.(*GetInfoRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+var _Watchtower_serviceDesc = grpc.ServiceDesc{
+	ServiceName: "watchtowerrpc.Watchtower",
+	HandlerType: (*WatchtowerServer)(nil),
+	Methods: []grpc.MethodDesc{
+		{
+			MethodName: "GetInfo",
+			Handler:    _Watchtower_GetInfo_Handler,
+		},
+	},
+	Streams:  []grpc.StreamDesc{},
+	Metadata: "watchtowerrpc/watchtower.proto",
+}

lnrpc/watchtowerrpc/watchtower.proto

@@ -0,0 +1,28 @@
+syntax = "proto3";
+
+package watchtowerrpc;
+
+option go_package = "github.com/lightningnetwork/lnd/lnrpc/watchtowerrpc";
+
+service Watchtower {
+        /** lncli: tower info
+        GetInfo returns general information concerning the companion watchtower
+        including it's public key and URIs where the server is currently
+        listening for clients.
+        */
+        rpc GetInfo(GetInfoRequest) returns (GetInfoResponse);
+}
+
+message GetInfoRequest{
+}
+
+message GetInfoResponse {
+        /// The public key of the watchtower.
+        bytes pubkey = 1 [json_name = "pubkey"];
+
+        /// The listening addresses of the watchtower.
+        repeated string listeners = 2 [json_name = "listeners"];
+
+        /// The URIs of the watchtower.
+        repeated string uris = 3 [json_name = "uris" ];
+}